Guide device for the automatic production of sewing designs with a sewing machine



L. BONO GUIDE DEVICE FOR THE AUTOMATIC PRODUCTION OF SEWING Nov. 26, 1963 I DESIGNS WITH A SEWING MACHINE 7 Filed April 30, 1962 2' Sheets-Sheet 1 Nov. 26, 1963 BONO 3,111,919

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45 AM; 7/412 whzw United States Patent GUIDE DEVICE FOR THE AUTOMATIC PRODUC- TION 0F SEWING DESIGNS WITH A SEWING MACHINE Luigi Bonn, Pavia, Italy, assignor to Necchi Societa per Azioni, Pavia, Italy Filed Apr. 30, 1962, Ser. No. 191,119 Claims priority, application Italy June 15, 1961 4 Claims. (Cl. 112103) This invention relates in general to new and useful improvements in sewing machine construction, and more particularly to a novel mechanism in a sewing machine for automatically producing sewing designs.

A primary object of the invention is to provide a device for controlling the automatic production of sewing designs with a sewing machine, with the sewing of the designs being carried out by cams connected to the mechanisms which normally control the relative displacement of the fabric relative to the needle of the sewing machine, with the cams being arranged so that after the sewing of the design having a predetermined number of stitches, the fabric is shifted to permit further sewing in a similar manner spaced from the initial stitching.

Another object of the invention is to provide a device for producing sewing designs which device relies upon a cyclic regulation of mechanisms of the sewing machine to produce a step-by-step advancement of fabric, with each advancing of the fabric taking place after the sewing of a predetermined number of stitches.

Another object of this invention is to provide a novel cam assembly for controlling the automatic production of sewing designs with a sewing machine, the cam assembly including first and second cams carried by a continuously rotating shaft, with one of the cams being secured to the shaft for rotation therewith, and the other of the cams being rotatable relative to the shaft and having means releasably locking the same to the shaft whereby one of the cams is continuously rotating and the other of the cams is periodically rotated, with the two cams acting upon the fabric positioning means for the purpose of producing the desired sewing design.

Another object of this invention is to provide a novel cam assembly for controlling the automatic production of sewing designs with a sewing machine, the earn assembly being carried by a continuously rotating shaft and including a first cam fixedly secured to the shaft for continuously rotating therewith, the first cam having a bushing on which a second cam is rotatably journaled, the second cam having associated therewith a ratchet gear and the bushing carrying a pivotally mounted pawl for engagement with the ratchet gear to effect the locking of the second cam to a bushing for rotation with the first cam, and the pawl having an extension which is engageable by a stop element during the rotation of the cams to release the ratchet gear periodically so that the first cam will continue to rotate while the second cam remains stationary with the second cam controlling the periodic shifting of fabric while the first cam constantly controls the shifting of fabric.

t will be clearly evident from the following description that the invention is particularly useful for automatically controlling mechanisms adapted to displace fabric in two directions perpendicular to each other so that it is possible to cover a fabric with a high number of stitches and thus to darn wide zones which are torn or worn. It is therefore a further object of this invention to provide a cam assembly for controlling the shifting of fabric with respect to a needle of a sewing machine wherein the sewing design produced will be one of a back and forth movement in parallel relation so as to produce a suitable pattern for darning fabrics.

3,111,919 Patented Nov. 26, 1963 With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a top view of the cam assembly in accordance with this invention.

FIGURE 2 is a bottom view of the cam assembly of FIGURE 1.

FIGURE 3 is a rotated vertical sectional view taken along the line III--III of FIGURE 1 and shows the specific construction of the cam assembly.

FIGURE 4 is a horizontal sectional view taken along the line lV-IV of FIGURE 3 showing further details of the cam assembly and showing in part other components of the mechanism.

FIGURE 5 is a rotated fragmentary vertical sectional view taken along the line VV of FIGURE 4, and shows the mounting of the pawl.

FIGURE 6 is a side elevational view of the sewing machine on a reduced scale with portions of the sewing machine broken away and shown in section and illustrating the use of the cam assembly.

FIGURE 7 is a horizontal sectional view taken along the line VII-VII of FIGURE 6 and shows further the details of the sewing machine and the mechanism controlled by the cam assembly.

FIGURE 8 is an enlarged fragmentary transverse vertical sectional view taken along the line VIII-VIII of FIGURE 7 and shows the details of the means for shifting a fabric holding frame of the sewing machine.

FIGURE 9 is a partial schematic example of the sewing design which can be obtained by the cam assembly when applied to the sewing machine.

FIGURE 10 is a more detailed schematic example of the sewing design of FIGURE 9.

FIGURE 11 is a schematic view showing two sewing designs similar to that of FIGURE 9 superimposed and rotated degrees with respect to each other.

Referring now to the drawings in detail, and more particularly to FIGURES 1 through 4, it will be seen that the cam assembly includes a bushing 1 which is provided with an integral cam 2 which is disposed adjacent the upper end thereof. At the lower end of the bushing 1 there is disposed an outwardly flared collar 3 which secures a ring 4 to the bushing 1. The outline of the ring 4 is best shown in FIGURE 2.

The bushing 1 has a shoulder 5 which opposes the ring 4 and between the ring 4 and the shoulder 5 there is mounted on the bushing 1 a ring 6 which is freely rotatable on the bushing 1. A cam 7 is secured to the ring 6 by welding or by other means, with the cam 7 being disposed adjacent the cam 2.

Due to the fact that the cam 7 is carried by the ring 6 and since the ring 6 is rotatable on the bushing 1, it will be readily apparent that the cam 7 is rotatable relative to the cam 2. In order to couple the cams 2 and 7 for rotation, there is provided a ratchet coupling which includes a gear ring or tubing 8 mounted on the ring 6 and secured thereto. The coupling also includes a pawl which is in the form of a small lever 9 which is pivotally mounted on the ring 4 by means of a pivot pin 10 which may be in the form of a screw threaded into the ring 4. The pawl 9 is seated in a recess 11 in the bottom face of the ring 4 and has a tooth 12 which passes through a slot in the ring 4 for engagement with the ratchet gear 8. A spring 13 is secured to the pawl 9 and has the opposite end thereof pressing against a support 14 of the ring 4 with the spring 13 acting to normally hold the pawl normally in locking engagement with the ratchet gear 8 so that the cam 7 rotates with the cam 2.

The bushing 1, as is shown in FIGURES 6 and 7 of the drawings, is mounted on an upstanding continuously rotating shaft 16 of a sewing machine for constant rotation therewith. The bushing 1 is supported by a support of a conventional type of sewing machine within the frame of the sewing machine. The support 15 is pivoted by means of a pin 17 relative to the frame of the sewing machine below the shaft 16 and carries slidable means (which are conventional, but not shown herein) which are capable of engaging in keyways 13 of the bushing 1 and similar keyways formed in the lower end of the shaft 16. The support 15 has a circular portion 19 (FIGURE 4) which is interrupted by two grooves 20 disposed in diametrically opposite relation and suitably oriented on the support 15.

The pawl 9 has a projecting end 21 which lies in the same plane as the grooves 20. When the end of the pawl 9 is at one of the grooves 20, spring 13 acts to push the tooth 12 of the pawl 9 against the ratchet gear 8 so that the cam 7 is momentarily rigidly connected with the bushing 1 and rotates with the bushing 1 and with the cam 2 in the direction indicated by the arrow X in FIGURE 4. However, when the rotation of the bushing 1 causes the end of the pawl 9 to press against and slide against the circular profile 19, the pawl 9 is pivoted to move the tooth 12 out of engagement with the ratchet gear 8 so that the cam 7 is released from the bushing 1 and does not rotate.

The circular profile 19 is shown in FIGURES 6 and 7 as being integral with the support 15. However, it could also be considered to be attachable to the support 15 so that it could be replaced by other profiles having a different number and arrangement of the grooves 20 so as to make it possible to vary the drive relationship of the connection between the cam 7 and the bushing 1 and therefore the sewing designs obtainable utilizing the cams 2 and 7.

It is to be understood that the cams 2 and 7 could, for instance, be connected with two known mechanisms connected with the feed dog of a sewing machine and be adapted respectively, to control the traditional feed move ments of the dog in one direction and to displace the dog in a direction perpendicular to the direction of feed so that the fabric is displaced in any desired direction. However, in FIGURES 6 and 7, the cams 2 and 7 are illustrated, by way of example, as controlling the movements of a fabric holding frame 22 which is movable on a base 23 of the sewing machine relative to a needle 24 of the sewing machine. In accordance with the use of the cam assembly in FIGURES 6 and 7, means which connect the cams 2 and 7 to the frame 22 include two feelers 25 and 26 which are engaged with the cams 2 and 7, re spectively. The feelers 25 and 26 are rigidly connected, by means of coaxial shafts 27 and 28, with levers 29 and 30, respectively, arranged below the base 23 of the sewing machine. The lever 30 is connected by means of a tie rod 31 to another lever 32 which is pivoted at one of the ends thereof to the base 23 by means of a pin 33. The other end of the lever 32 is connected by means of a tie rod 34 to a guide 35 which is displaceable within seats 36 provided below the base 23 and which guide 35 is rigidly connected to a slide 37. The slide 37 is arranged beneath an opening 38 formed in the base 23 and has a groove 39 receiving an edge of a horizontal plate 40 which is fastened below the base 23 by means of screws 41 (FIGURE 8).

A spring 42 is fastened to the lever 32 and to the base 23 to hold the feeler 26 against the peripheral surface of the cam 7. In this manner, the feeler 26 follows the cam 7 and the cam 7 controls the displacement of the slide 37 in the direction indicated by the arrow y in FIGURE 7. The other lever 29, which is rigidly connected with the feeler 25, is connected to a double armed lever 43 (bellcrank) by means of a tie rod 44. The lever 43 is also pivoted on the pin 33 and carries a pin 45 which can slide in a groove 46 in the bottom of a slide 47. The groove 46 is disposed parallel to the guide 35 and the slide 47 is mounted on the slide 37 by means of a guide 43 which is slidable on the slide 37. The slide 37 is rigidly connected to the guide 48 for movement therewith.

A spring 49 is fastened to the lever 43 and to the base 23 of the sewing machine to hold the feeler 25 against the periphery of the cam 22. In this manner, the cam 2 controls the displacement of the slide 47 along the axis of the guide 45 in the direction indicated by the arrow w in FIGURE 7, the direction being at right angles to the direction of the displacement of the slide 37 in the direction indicated by the arrow y. The slide 47 has holes 50 in which there are inserted pins 51 of the fabric holding frame 22 so that the frame 22 may be moved by the slide 47 above the base 23.

The cam rotates in the direction indicated by the arrow x in FIGURES 1 and 7, and presents successively in front of the feeler 25 two profile sections a and b having gradually increasing and decreasing radii, respectively. The sections a and b are connected together by two sections 0, one of which is pointed and the other of which is recessed.

The circular profile 19 is oriented on the support 15 in such a manner that the end 21 of the pawl 9 slides against this profile each time the cam 2 brings the sections it or b of the profile thereof in contact with the feeler 25. Under these conditions, the tooth 12 of the pawl does not engage the ratchet gear 8 so that the cam 7 idles on the bushing 1 and is held stationary, thus maintaining the slide 37 stationary. At the same time, the cam 2 controls the displacement of the slide 47 in the direction indicated by the arrow w (FIGURE 9). In this way, the sewing sections 52 of FIGURE 9 are formed.

However, when the cam 2 brings one of the connecting sections c in contact with the feeler 25, the end 21 of the pawl 9 is at one of the grooves 20 of the circular profile 19 and therefore the spring 13 is free to force the tooth 12 of the pawl into engagement with the ratchet gear 8. During the contact of the feeler 25 with the 0 sections of the cam 2, the slide 47 remains practically stationary while the cam 7 rotates in the direction indicated by the arrow x (FIGURE 2) and displaces the slide 37 in a direction indicated by the arrow y (FIGURE 9) so that one of the lengths of sewing 53 is performed, as is shown in FIGURE 9. The lengths of sewing 53 will obviously be controlled by the configuration of the cam 7 and the differences in radius of the two successive points on the cam 7 engaged by the feeler 26.

Finally, upon each rotation of the cam 2, the cam 7 is imparted two steps of angular amplitude corresponding to the amplitude of the grooves 20. In general, the number of steps required to effect a complete sewing cycle and therefore return the cams 2 and 7 at the same time into the initial positions thereof is determined by the minimum common multiple between the number of grooves 20 and the number of steps of the cam 7 necessary for the cam 7 to rotate one revolution.

The complete sewing cycle obtained with the cams 2 and 7 operating in the manner illustrated in the drawings assumes the appearance of FIGURE 10, and the stitcln'ng resulting from the sewing cycle covers the fabric with a large number of stitches, making it possible to darn large torn or worn areas. By effecting a second sewing cycle after having rotated the fabric degrees, the darning assumes the appearance shown in FIGURE 11.

The cam 7 shown in the drawings has an undulated profile, the valleys 54 of which are arranged at constant angular distances corresponding to the size of the steps of the cam controlled by the grooves of the circular profile 19. The feeler 26 is engaged in the valleys 54 after each stepped rotation of the cam 7. In this way, the feeler 26 locks the cam and prevents it from undergoing undesired rotation when the circular profile 9 controls the opening of the coupling between the cam 7 and the bushing 1. It will be understood, however, that the cam 7 could also have a smooth profile and be rigidly connected with a drum on which there presses suitable brake means contained in the frame of the sewing machine and of a nature suitable to present the undesired rotations of the cam 7. Such a drum could be represented, as an example, by a ring concentric with the bushing 1 on which the brake means would exert a pressure sufiicient to counterbalance the eccentric pressures of the feeler 26 on the cam 7 Although the use of the cam assembly in a sewing machine has been disclosed with respect to only one attachment of the sewing machine, it is to be understood that the invention is not so limited. Minor variations may be made in the invention within the scope and spirit of the invention, as defined in the appended claims.

I claim:

1. A fabric feed for a sewing machine comprising a fabric holding frame, first linkage connected to said frame for moving said frame in a transverse direction, second linkage connected to said frame for moving said frame in a longitudinal direction, a constantly rotating shaft, a pair of cams carried by said shaft and driven thereby, means mounting a first of said cams for constant rotation therewith, a second of said cams having means for mounting the same on said shaft for rotation relative thereto, and coupling means connected to said second cam for periodical rotation with the shaft, and cam followers cooperating with said cams and connected to said linkages for actuating the same.

2. The fabric feed of claim 1 wherein said first cam is secured to a bushing forming part of said first cam mounting means, said second cam being rotatably journaled on said bushing with said bushing forming part of said second cam mounting means.

3. The fabric feed of claim 2 wherein said coupling means includes a ratchet gear connected to said second cam, a pawl pivotally mounted on said bushing, resilient means for holding said pawl in engagement with said ratchet gear, and means engageable With said pawl to selectively move said pawl between engaged and released positions.

4. The fabric feed of claim 1 together with brake means associated with said second cam for preventing rotation of said second cam when said pawl is released from said ratchet gear.

References Qited in the fiie of this patent UNITED STATES PATENTS 268,804 Keith et al. Dec. 12, 1882 1,603,644 Sibbald et a1. Oct. 19, 1926 2,485,738 Jeschke Oct. 25, 1949 2,939,414 Slinn June 7, 1960 

1. A FABRIC FEED FOR A SEWING MACHINE COMPRISING A FABRIC HOLDING FRAME, FIRST LINKAGE CONNECTED TO SAID FRAME FOR MOVING SAID FRAME IN A TRANSVERSE DIRECTION, SECOND LINKAGE CONNECTED TO SAID FRAME FOR MOVING SAID FRAME IN A LONGITUDINAL DIRECTION, A CONSTANTLY ROTATING SHAFT, A PAIR OF CAMS CARRIED BY SAID SHAFT AND DRIVEN THEREBY, MEANS MOUNTING A FIRST OF SAID CAMS FOR CONSTANT ROTATION THEREWITH, A SECOND OF SAID CAMS HAVING MEANS FOR MOUNTING THE SAME ON SAID SHAFT FOR ROTATION RELATIVE THERETO, AND COUPLING MEANS CONNECTED TO SAID SECOND CAM FOR PERIODICAL ROTATION WITH THE SHAFT, AND CAM FOLLOWERS COOPERATING WITH SAID CAMS AND CONNECTED TO SAID LINKAGES FOR ACTUATING THE SAME. 